Conventional packaging for the retail sale of consumer products has evolved to include display packs that not only allow unobstructed viewing of a product without opening the packaging, but also prevent tampering with the product, deter theft of the product, and limit retailer costs of an unsaleable product due to damage to the packaging. Among the types of consumer packaging developed to address these needs is a clear plastic blister pack in combination with a cardboard, corrugated fiberboard, or paperboard frame that encloses the outer edges of the blister pack. The product is enclosed inside the blister pack, and the combination of the blister pack and the corrugated frame prevents easy access to the product. This type of packaging deters theft by providing a bulky package, and it also provides a protective shield to the enclosed product while still allowing a consumer to view the product.
Traditionally, the corrugated frame used in combination with plastic blister pack is made up of two sheets of material adhered together with an adhesive, such as a hot melt glue, a heat-sensitive adhesive, or a cohesive contact adhesive. However, these adhesives and their respective application processes have several disadvantages. For instance, hot melt glues are typically difficult to apply in a controlled fashion and the quality of the resulting seal varies accordingly. Heat-sensitive adhesives often provide ineffective seals when used with corrugated substrates because the corrugated sheets are poor heat conductors. Such adhesives are also difficult to use in a high volume manufacturing process where corrugated frames must be stacked in an efficient manner because the adhesive is slow to dry and is also susceptible to smearing when coming into contact with another surface. Furthermore, as the corrugated frames are stacked higher and higher, the accumulation of weight in the stack increases the possibility of the frames adhering to each other once the adhesive has been applied. Finally, conventional cohesive contact adhesives also suffer from these and other drawbacks in that they are applied over the entire interior surface of the corrugated packaging, creating waste, slowing the production process, and inevitably leaving an undesirable adhesive residue on the plastic blister pack, which impacts the recyclability of the blister pack when separated from the corrugated frame.
The abovementioned conventional adhesives create excess waste both during the manufacturing process and once the product is removed from the packaging by a consumer. In recent years, there has also been an increased awareness of the environmental impact from the manufacture, use and disposal of product packaging. While both the plastic blister pack and corrugated frame used in conventional packaging are separately recyclable, the adhesive is not and can impact the recyclability of the rest of the packaging. It is therefore desirable to use an adhesive that causes a minimal environmental impact when disposed.
Accordingly, a need exists for a method of efficiently applying an adhesive for product packaging at high production rates that enables a combination plastic blister pack and corrugated product packaging container that is cost-effective to produce, environmentally friendly to manufacture and dispose, and sufficiently protects a product during shipping, handling, and display.